Role of copper in time dependent dielectric breakdown of porous organo-silicate glass low-k materials

The role of copper in time dependent dielectric breakdown (TDDB) of a porous low-k dielectric with TaN/Ta barrier was investigated on a metal-insulator-metal capacitor configuration where Cu ions can drift into the low-k film by applying a positive potential on the top while they are not permitted to enter the low-k dielectric if a negative potential is applied on the top. No difference in TDDB performance was observed between the positive and negative bias conditions, suggesting that Cu cannot penetrate TaN/Ta barrier to play a critical role in the TDDB of porous low-k material.